John Floyd Thomas Jr., a career criminal, pleaded guilty to seven murders but is suspected in numerous other slayings.

John Floyd Thomas Jr., 74, listens as charges against him are read in court. (Al Seib / Los Angeles Times )

A former insurance claims adjuster who was suspected of terrorizing women in the 1970s as the Westside Rapist has been sentenced to life in prison without the possibility of parole for seven murders that were committed in two waves of killings and sexual assaults.

John Floyd Thomas Jr., 74, sat with his hands manacled to a waist chain and used sheets of paper to shield his face from a photographer as he was sentenced for the killings that took place in a swath stretching from Inglewood to Claremont.

Detectives describe Thomas as one of the region's most prolific serial killers, saying that he remains a suspect in at least 10 to 15 additional slayings, based on the dates of the crimes and his method of killing.

"He has been my worst nightmare," said Tracy Michaels, who flew from Austin, Texas, to witness Friday's conclusion of a 35-year search for justice after her great-aunt, Elizabeth McKeown, was raped, strangled and stuffed in the trunk of her car. "For me the death penalty would've been too easy."

Michaels, who as a teenager lived with her great-aunt, asked Los Angeles County Superior Court Judge George G. Lomeli to "remove any comfort from this man's life.… Make the rest of his life feel like what he's made our lives feel like."

Police said the attacks targeted women who ranged in age from their 50s to their 90s, many of whom lived alone. The killer broke into their homes at night and raped and choked his victims until they passed out or died. Before he left, he would cover their faces with a pillow or blanket.

Thomas' sentence was part of a plea deal with prosecutors that Deputy Dist. Atty. Rachel Moser Greene described as "an act of pragmatism" rather than "an act of mercy."

She noted that capital punishment was not legal in California when all but one of the killings Thomas admitted to were committed. She said the death penalty would not have been relevant in this case because Thomas would probably die in prison during his appeals, given his age.

"This provides certainty and finality for surviving family members who lived with this for so long," Greene said.

Thomas was born in Los Angeles and was raised by an aunt and his godmother after his mother died when he was 12. He attended public schools, including Manual Arts High School, and briefly joined the U.S. Air Force in 1956.

At Nellis Air Force Base in Nevada, a superior described him as often late and slovenly. He received a dishonorable discharge, according to his military records. The next year, he was convicted of burglary and attempted rape, which put him in prison for nearly a decade.

Shortly after his release, authorities noticed a string of assaults on elderly white women. The attacker was dubbed the Westside Rapist at the time.

Most of the victims Thomas admitted slaying were killed in the 1970s, including McKeown, 67, in Westchester in 1976; Ethel Sokoloff, 68, in the Mid-Wilshire area in 1972; Cora Perry in Lennox in 1975; Maybelle Hudson, 80, Miriam McKinley, 65, and Evalyn Bunner, all in 1976 in Inglewood.

The attacks appeared to stop in 1978, when Thomas was convicted and sentenced to prison for the rape of a Pasadena woman. After his release in 1983, he moved to Chino, coinciding with a wave of rapes and killings that began in the Pomona Valley area.

Among Thomas' victims was Adrienne Askew, 56, who was found strangled in 1986 in her Claremont apartment.

About two years earlier, the body of her 85-year-old mother, Isabel, had been found in a vineyard near Ontario International Airport. The two women had shared an apartment. Authorities were never able to determine a cause of death for Isabel because of the condition of her body. Police officials suspect that she might also have been one of Thomas' victims but say investigators may never be able to prove a link.

In a statement read in court by the prosecutor Friday, Adrienne Askew's niece described Thomas as "a sadistic predator who preyed on the vulnerable."

Susanne Askew Livingston wrote that her aunt worked as a school crossing guard and librarian's assistant despite being developmentally disabled.

"Please never let him see the light of day, again," she implored the judge.

Brian Askew, Adrienne's nephew, recalled watching as an 8-year-old boy when his father broke down in tears after a phone call notified him of his sister's death. His father, who he said felt "tremendous amounts of guilt" for allowing his sister to live alone after their mother's death, passed away before Thomas was caught.

"When I think how my dad would've reacted, I get emotional," Askew said outside the courtroom.

The killings appeared to stop in 1989, the year Thomas took a job in the state workers' compensation agency in Glendale.